Technical Sgt. Carl Tyynismaa takes a drink of water after spending the day Monday, July 18, 2011 working on a KC-135 Stratotanker aircraft at Selfridge Air National Guard Base, Mich. The heat index on the flight line was above 100 degrees in mid-afternoon, causing Airmen at the base to drink extra water and take regular breaks in the shade. Tyynismaa is a crew chief assigned to the 127th Wing, Michigan Air National Guard, at the base. (USAF photo by Rachel Barton)